SPIE: EUV sources behind schedule

SAN JOSE, Calif. – Extreme ultraviolet (EUV) lithography is making progress, but the power source for the technology is behind schedule, warned keynote speakers at the SPIE Advanced Lithography conference here.

As reported, ASML Holding NV has recently shipped the world's first ''pre-production'' EUV lithography tool to a customer, reportedly Samsung Electronics Co. Ltd., sources said. That tool from ASML is called the NXE:3100, which is using a light source from Cymer Inc.

It's unclear if EUV is ready for prime time, as the power source and other technologies remain behind schedule. ''Our checks suggest throughput at the first (EUV) tool installation at Samsung by ASML is currently only 8-10 wafers per hour, well below the breakeven level relative to double patterning of about 50 wafers per hour,’’ said C. J. Muse, an analyst with Barclays Capital, in a new report.

One vendor even said that EUV is now measured by wafers per day-a disappointing measurement at best. EUV is a next-generation lithography (NGL) technology that was supposed to be inserted for production at the 65-nm node. But the technology has been delayed, due to the lack of power sources, defect free masks, resists and metrology infrastructure.

Still, leading-edge chip makers are banking on EUV for production fabs, in an effort to avoid the dreaded and costly double-patterning era for optical lithography. But chip makers have no choice but to go to double patterning. Experts believe that EUV is now targeted for production at the 16-nm node-or later.

Belgian research institute IMEC on Monday announced it has installed an NXE:3100 pre-production EUV machine from ASML at its Leuven facility.

''Tremendous progress has been made’’ on EUV, said Luc Van den hove, president and CEO of IMEC, during a keynote at SPIE, but the big challenge is to ''demonstrate production readiness.’’

With the NXE:3100, researchers at IMEC have demonstrated the ability to print 24-nm lines and 26-nm holes, he said. The tool was able to print 20-nm lines and space using dipole illumination techniques, he said.

Improvements have been made in resists, but there are still issues with power sources. ‘’We are behind schedule in power increases,’’ he said.

EUV has seen a factor of 20 in terms of improvement in productivity. ''We need a factor of 10 in improvement by the end of the year,’’ he said.

The power sources for EUV are late, the reticle technology is lacking, the resists are not ready yet, and some estimates put the cost of the first production tools at well over $100 million each. In addition both the sources and the tools themselves are currently massive in size compared to 193 nm immersion tools. I believe that currently EUV litho would be even more expensive than quadruple patterning, let alone double.